The present invention relates to a male electrical connector to be attached to a circuit board (hereinafter called “male connector”) and an electrical connector assembly for a circuit board (hereinafter called “connector assembly”) having the male electrical connector and a female electrical connector (hereinafter called “female connector”) to be attached to another circuit board.
Publication Reference has disclosed a connector assembly for a circuit board. According to Publication Reference, each of a male connector and a female connector is attached to a circuit board. Further, the male connector and the female connector are fitted with each other to connect in a direction perpendicular to a surface of the circuit board. Accordingly, when the male connector and the female connector are fitted, the circuit boards become parallel to each other. A terminal of the male connector forms a connection portion in a portion that extends outside a housing thereof along a surface of the circuit board. Further, the connection portion is connected to a corresponding circuit portion of the circuit board with solder.
Publication Reference: Japanese Utility Model Publication No. 3055703
In the female connector, a peripheral wall of a housing is situated outside with respect to a fitting portion of the male connector. Further, a top face of the peripheral wall faces a connection portion of the male connector. The top face of the peripheral wall is adjacent to and faces the connection portion of a terminal of the male connector.
The terminal of the male connector is connected with the circuit portion of the circuit board with solder in the connection portion. Molten solder rises from a solder connection surface of the connection portion due to surface tension. Further, the molten solder may reach a surface other than the solder connection surface that is tangent to the circuit portion. That is, a phenomenon called a “solder rising” occurs.
The molten solder rises to a side edge surface of the connection portion due to the solder rising; thereby forming a fillet shape portion between a side edge surface and a surface of the circuit portion, thereby improving strength of the solder connection.
The solder rising does not stop at the side edge surface of the connection portion. Instead, the solder rising proceeds further to reach a facing region in which the solder connection surface faces an opposite side surface of the solder connection surface, or a top face of a peripheral wall of the female connector (mating connector).
Further, a swelling in the facing region of the connection portion may be formed there. The solder connection of the connection surface can be visually confirmed due to the solder rising. On the other hand, the connection portion may collide with the top face of the housing peripheral wall of the female connector due to the solder swelling in the facing region of the connection portion, thereby making it difficult to fit the male connector and the female connector.
To this end, in Publication Reference, a space is formed as an escape portion, so that it is easy to fit the male connector and the female connector even when the male connector has the solder swelling in the connection portion. The escape portion is recessed from the top face of the housing peripheral wall of the female connector.
According to Publication Reference, the escape portion of the female connector can prevent a trouble caused by the solder swelling in the connection portion of the terminal of the male connector. It should be noted, however, that it is necessary to provide the escape portion with a depth sufficiently larger than an expected amount of the solder swelling to certainly prevent the trouble. When a size of the escape portion increases, a size of the female connector increases as well in a fitting direction unless a special attention is paid to a size and an arrangement of the terminal.
As described above, the solder swelling caused by the solder rising can inhibit a complete fitting of the male connector and the female connector. Further, when an automatic quantitative soldering is conducted, an amount of the solder may become insufficient in the solder connection portion by an amount corresponding to the solder rises, thereby decreasing the connection strength. Accordingly, the escape portion of the female connector may prevent the problem in the first case, but does not in the latter case.
In view of the problems described above, an object of the present invention is to provide a male connector for a circuit board and a connector assembly comprising the male connector and a female connector for a circuit board. In the present invention, it is possible to prevent the male connector from insufficiently fitting to the female connector, and to provide solder with a sufficient amount in a solder connection portion. Further, it is possible to minimize a solder rising and maintain strength of a fillet shape portion.
Further objects of the invention will be apparent from the following description of the invention.